Yarn heaters

ABSTRACT

A yarn heater comprising two rollers having spaced substantially parallel axes, and two heating members extending longitudinally on opposite sides of the space between said rollers and having heating surfaces facing into the space between said rollers. The heating members may be mounted to be pivoted or slid outwardly away from the space between said rollers. A wrap detector or a further heating member may be mounted in said space. Cooling members may be mounted laterally adjacent to the heating members.

UnitedStates Patent: [191 Whittaker YARN HEATERS [751 Inventor: Harold Whittaker, Manchester,

England [73] Assignee: Carding Specialists Co. Limited.

Halifax. Yorkshire. England [22] Filed: May 3], i972 [2i] Appl. No.: 258,330

[30] Foreign Application Priority Data June 18. I97] (ireal Britain 28(146/71 Dec. H). W7] (ireat Britain 57484/7] [52] US. Cl. 219/470, 28/62 [5l] Int. Cl. HOSb 1/02 [58] Field of Search 219/469-471,

219/388, 2l6. 530; 28/62; 57/34 HS [56] References Cited UNITED STATES PATENTS 3.472.011 10/1969 Scragg 2|9/388 X l l Oct. 22, 1974 FOREIGN PATENTS OR APPLICATlONS l,l73.49) 12/1969 Great Britain 39/388 Assistant lituniim'r i red E. Bell Attorney. Agent. or Finn-Stevens, Davis, Miller & Masher [57] ABSTRACT A yarn heater comprising two rollers having spaced substantially parallel axes, and two heating members extending longitudinally on opposite sides of the space between said rollers and having heating surfaces facing into the' space between said rollers. The heating members may be mounted to be pivoted or slid outwardly away from the space between said rollers. A wrap detector or a further heating member may be mounted in said space. Cooling members may be mounted laterally adjacent to the heating members.

1] Claims, 8 Drawing Figures PATENTED our 2 2 I974 SHEET 2 BF 6 This invention relates to means for heating yarn during processing of the yarn.

A known form of yarn heater comprises two rollers having spaced substantially parallel axes and a heater positioned between the rollers and having outwardlyfacing convex surfaces over which the yarn passes as it travels from one roller to the other. The yarn is conventionally taken in a number of wraps round the rollers and thus makes a number of passes over the surface of the heater. The heater may be electrical or may utilise a hot circulating fluid. The temperature of the heater, the size of the heater and the number of passes of the yarn over the heater will determine the temperature to which any given yarn is varied.

If yarn breakage in a heater of this form should occur, then the yarn will commence to wrap itself around one or other of the rollers and will eventually jam between that roller and the heater with consequent damage to the heater or to the roller and the drive thereto. 1

There is also substantial loss of heat by radiation to atmosphere from the outwardly-facing heater surfaces.

According to the .present invention a yarn heater comprises two rollers having spaced substantially parallel axes, and two heating members extending longitudinally on opposite sides of the space between the rollers and having heating surfaces facing into the space between the rollers.

In this arrangement it will be seen that there is a substantially enclosed space defined by the two rollers and the two heaters. 'As the two rollers will generally have at least part of their curved surface faced by the heating surfaces then the rollers will warm up very much more quickly than in the known arrangement. Furthermore, as the heating surfaces of the heating members face towards each other into the substantially enclosed space there is going to be smaller heat loss to atmosphere than was so in the earlier construction.

While the temperature of the two heating members may be controlled independently, it is desirable for such control to be common.

Preferably the heating surface of the or each heating member is convex towards the space between the rollers, and the or each convex heating surface twice in tersects the external common tangent plane to the rollers at the respective side of the space.

With this arrangement the yarn will run in contact with the heating surfaces of the members when passing between the two rollers, and heat transfer to the yarn will thus be maximised. However, it is not necessary for the yarn to run in contact with the heating surfaces, and these surfaces may be plane or even concave if desired.

The enclosed space inevitable in the construction according to the invention may make it difficult to lift yarn from the heating surfaces if the machine is stopped, and may make threading of yarn through the apparatus somewhat more difficult than in conventional yarn heaters. To overcome these disadvantages the two heating members are preferably mounted so that they may be moved outwardly away from the space between the rollers. Such movement may conveniently be effected by pivoting or sliding of the heating members.

Preferably a wrap detector is mounted in the space between the rollers and the heating members. Individual warp detectors adjacent to each of the two rollers may be used, but desirably a common wrap detector having parts adjacent to both rollers can be provided.

The design of this yarn heater with the space wherein a wrap detector may be mounted is a great advantage over conventional heaters, where no wrap detector can be provided. The wrap detector will detect a wrap of yarn building up on either roller after a yarn breakage and can stop the whole yarn processing operation before damage to any part of the apparatus occurs. The wrap detector may take any one of a number of forms well known to those skilled in the art.

As an alternative to a wrap detector a further heating element may be provided in the space between the rollers, such element preferably being double-sided so that in each pass between the rollers the yarn runs through a channel between the surfaces of two heaters and is thus heated on both sides. More rapid heating of the yarn can be accomplished in this manner. A wrap detector external of either or both rollers may be used in conjunction with this dual heating arrangement.

In many yarn processing operations yarn coming from a heater is caused to pass over a directionchanging element or a processing member, and when synthetic yarns are processed at high temperatures it can often happen that suchpassage causes the yarn to become loopy and weaker.

In one form of the invention, therefore, the heating members may have a lateral extent less than that of the rollers, and cooling members of similar shape to the heating members are positioned alongside the heating members at the yarn exit side of the rollers.

Thus, after the heat treatment the yarn is cooled before leaving the rollers and possible damage to the yarn in a subsequent passage over a further element is reduced or avoided.

The yarn heating and cooling members may be physically separate and separated by an air gap for insulation purposes, or they may be assembled together as a unit and separated by heat insulating material. Provision is made in the cooling members for a cooling fluid, preferably water, to be circulated therethrough. The temperature of the cooling fluid is preferably commonly controlled, although individual control is possible.

In order that the invention may be better understood specific embodiments of yarn heaters constructed in accordance therewith will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a first yarn heater;

FIG. 2 is an end elevation, partly in section of the yarn heater of FIG. 1;

FIG. 3 is a section on the line IIIIII of FIG. 2;

FIG. 4 is a plan view of part of a second embodiment yarn heater;

FIG. 5 is a section on the line V-V of FIG. 4;

FIG. 6 is a section on the line VIVI of FIG. 4;

FIG. 7 is an end elevation of a third embodiment of yarn heater; and

FIG. 8 is an elevation of part of a fourth embodiment of yarn heater.

Referring now to FIGS. 1 to 3, a yarn heater comprises two rollers l and 2 having spaced substantially parallel axes. Itis generally desirable to have the roller axes somewhat offset from an exactly parallel relationembodiment of ship, in order to separate the turns of yarn axially along the rollers. Offsetting of about is'commonly used, and such an arrangement is intended to be included within the tern substantially parallel. The rollers are keyed onto shafts (not shown) journalled for rotation in hearings in a housing 3 and may be driven from a drive shaft passing through an extension 4 of the housing. The drive to the rollers may be of any conventional form, such as a belt and pulley or a gear system, and as it forms no part of the present invention it has not been described in detail herein.

Two heating members shown generally as 5 and 6 extend longitudinally along opposite sides of the space between the rollers 1 and 2. The two heating members are of identical construction except for being of opposite hand, and only the heating member 5 will be described in detail, corresponding elements of the heating member 6 being indicated on the drawings by the same reference numerals used for the heating member 5 with the addition of the suffix a. The heating element 5 comprises a carrier 7, an electrical heating element 8 including resistance wires supported on an insulating plate and a heating plate 9. The heating plate 9 is formed with studs 10 and 11 passing through aligned holes in the heating element 8 and carrier 7 and having threaded ends on to which nuts 12 and 13 respectively are secured. Insulating washers 14 and 15 are located between the heating element 8 and the carrier 7 to space these apart and reduce conductive heat loss to the carrier 7. The heating plate 9 is formed with a bore l6 inwhich is mounted a temperature sensor which may be connected to an electrical circuit. The carrier 7 is formed of ferromagnetic sheet material and is bent to forma' flange section 17. At the juncture between the flange section 17 and the main section of the carrier there is mounted one plate of a hinge 18, the other plate of which is secured a frame 180 fixed to the housing 3. The heating member is thus pivotally mounted on the housing to move between a firstposition immediately adjacent to the space between the rollers, as shown in the Figures, and a second position removed from said space as indicated by the broken outline of the carrier 7 in FIG. 3. To facilitate manual handling of the carrier this has a knob 19 of a material with a low heat conductivity secured to the carrier by a bolt 20.

Mounted on the frame 180 is a magnet 21 secured by a bolt 22 and nut 23 of non-magnetic material, and spaced from the frame 180 by a spacing washer 24 also of non-magnetic material. A further magnet 25 is secured to a forward part 26 of the frame,-which is itself non-magnetic,-by a bolt 27 screwed into a tapped bore 28. It will readily be understood that the magnet 21 can attract the flange 17 of the carrier and thus hold the heating member in its first position, and the magnet 25 can attract the flange 17 to hold the heating member in its second position after manual movement of the heating member sufficiently far to bring the flange 17 into the region of influence of the magnet 25.

As best seen in FIG. 2 the heating plates have heating surfaces 29 which are convex towards the space between the rollers, these surfaces being made up of a plane section 30 substantially parallel to a line joining the axes of the rollers, and two sections 31 and 32 inclined to such a line. The heating surface thus twice intersects the external common tangent plane A-A to the rollers at the respective side of the space.

Positioned in the space between the rollers 1 and 2 and the heating surfaces 29 and 29a is a wrap detector shown generally as 32. The wrap detector comprises a stem 33 having a boss 34 at one end thereof, and a plate 35 comprising a centre portion 36 and two wings 37 and 38 secured to the stem by welding 39. The detector may pivot by movement of the stem 33 about a spindle 184 secured by a nut 185 to the forward part 26 of the frame 180. The detector is held against clockwise movement from the position shown in FIG. 2 by engagement of the boss 34 with a stop 40.

The electrical heating elements 8 and 8a are desirably controlled in unison so that they attain the same temperature, and it is therefore preferred to use electrical windings connected in series. To prepare the apparatus for use the two heating members are warmed up to the desired temperature, with the rollers 1 and 2 running so that these are also heated. The heating members are then moved to their second positions shown in the broken lines in FIG. 3 and the yarn to be heated is threaded to make multiple passes over the rollers 1 and 2, which are arranged to rotate in a clockwise direction as seen in FIG. 2. The heating members are then moved back to the positions shown in FIG. 2 whereupon the heating surfaces will contact the yarn so that as the rollers rotate the yarn runs in contact with these surfaces. The yarn is then run through the heater, the rate of travel of the yarn and the temperature of the heating elements being controlled to give the required degree of yarn heating. Should the yarn break while in the heater, the yarn will start to wrap around one of the rollers and thus build up in thickness on that roller. The wrap of yarn will contact the appropriate wing 37 or 38 of the wrap detector and will cause this to move in an anticlockwise direction. When this deflection reaches a certain degree then the wrap detector can operate a switch (not shown) which electrically controls a yarn cutting and holding device located above the heater. The yarn is then cut and held against further feed into the heater, whereupon the rollers may be stopped, the heating members moved to their second positions as shown in broken lines in FIG. 3 and the wrap cleared from the rollers. The yarn can then be rethreaded and the apparatus started up again.

FIGS. 4 to 6 show an alternative form of heating assembly that may be used in the invention. This assembly comprises two mounting elements 60 and 61 which may be secured to a housing such as 3 in FIG. 1 by bolts passed through bores 62 and 63 respectively. A front plate 64 is secured to the front faces of the mounting elements and this plate supports a wrap detector assembly 65 similar to that described with reference to FIGS. 1 to 3.

Two heating members 71 and 72 are provided, each one lying to one side of the spacebetween two rollers which are not shown in detail but are partially indicated in broken lines 73 and 74 in FIG. 5. The heating member 71 has a rearwardly extending flange 73 to which a guide rod 74 is secured by a nut '75 engaging a threaded end of the rod 74, the threaded end extending from an enlarged collar 76. The heating member 72 has a similar flange 77 to which is secured a guide rod 78 having an enlarged collar 79 and a threaded end to which is fitted a nut 80. The guide rod 78 passes through holes 81 and 82 in the mounting elements 61 and 60 respectively and through a hole 83 in the flange 73. The guide rod 74 passes through holes 84 and 85 in the mounting elements 60 and 61 respectively and through a hole 86 in the flange 77.

Guide rods 74 and 78 also pass through bores in respective ones of elements 87 and 88 which have circular section pins such as 89 extending rearwardly therefrom. The pin 89 engages in a groove 90 in the upper edge of a plate 91 and the corresponding pin on the lower member 88 engages in a groove 92 in the lower edge of the plate 91. The plate 91 is mounted for pivotal movement on a spindle 92, on which the wrap detector is also pivotally mounted. The plate 91 interlocks the elements 87 and 88 so that movement of one of the guide rods 74 and 78 will result in opposite movement of the other of these guide rods. The two heating elements are shown in FIG. 4 in their positions immediately adjacent to the space between the rollers and it will be appreciated that if one of the heating members is moved laterally away from this space then the linkage described will cause a similar movement of the other heating member away from the space in the opposite direction. This then leaves the rollers free to be threaded, or for any yarn wrap to be removed.

An alternative form of heating member assembly is shown in FIG. 6, and it will be understood that this can be used in either of the forms of apparatus so far described. In this arrangement a plate 90a of conductive material is formed with studs 91a and 92a which pass through holes in a heating element 93 and a piece of heat insulating material 94 to project from holes through the carrier 95. Nuts 96 and 97 threaded on to these studs hold this assembly together as a unit, and the plate 90 has a bore in which a temperature sensitive element 98 can be located. The plate 90a has projecting strips 99 and 100 at the upper and lower edges thereof. The heating member is fitted with aremovable heating surface 101 which is formed with grooves 102 and 103 which may be slidably engaged with the projecting strips 99 and 100. A spring loaded locking ball 103 is secured to the insulating material 94 and can engage in a depression 104 formed in an upper flange 105 of the heating surface 101. Thus the surface 101 is readily removable and replaceable merely by sliding it off the remainder of the heating assembly.

FIG. 7 shows a further modified arrangement utilising heating members 110, 111 pivoted to a housing in a similar manner as described'in FIGS. 1 to 3. Each heater assembly is of a construction similar to that shown in FIG. 2, but the heating faces 112, 113 respectively of the heating members are plane rather than convex towards the space between the heaters, and do not intersect the common external tangents to the two rollers 114, 115 at the respective sides of the assembly. Accordingly, the yarn does not run in contact with the heating surfaces 112, 113 when passing between the two rollers, and there is no heat transfer to the yarn by direct conduction from the heating surfaces. Heaters of this type can of course be used in the arrangement of FIG. 1. FIG. 7 also shows the use of a further heating unit 120 positioned in the space between the rollers 114, 115 and the heating members 110 and 111. In this arrangement, therefore, in each pass between the rollers the yarn runs through a channel between the surfaces of two heating units and is thus heated on both sides so that more rapid heating of the yarn can be accomplished. This arrangement excludes the use of a wrap detector mounted in the space between the rollers, but an externally mounted wrap detector could be used in conjunction with this assembly. FIG. 7 also illustrates the provision of a cover 121 hinged at 122 to one of the heating members and surrounding part of v the circumference of the top roller 114. Such a cover may be uitlised in conjunction with any one of the forms of the apparatus described herein and will serve to reduce the heat loss from the apparatus.

FIG. 8 is a view taken on the face of a modified heater plate similar to that shown in FIG. 1. In this construction three units are secured to a common carrier such as the carrier 7 shown in FIG. 2. The first of these units is a heating member similar to that shown in FIG. 2 and receiving electrical power from a supply cable 131, the second unit is a block 132 of heat insulating material, and the third unit is a cooling unit 133 cooled by circulating fluid fed to the unit by a pipe 134 and returning from the unit by way of a pipe 135. The lateral extent of the heating member 130 is thus less than that of the rollers, and the cooling unit is positionedalongside the heating member at the yarn exit side of the rollers. Thus, after the heat treatment the yarn is cooled by running in contact with the cooling unit before leaving the rollers, so reducing possible damage to the yarn during later processing.

It will be evident that modifications to the apparatus shown in the drawings can readily be made. The heating members may be heated by a hot fluid circulation system. The form of the heating members, and of the cooling members if provided, and the arrangement for mounting these so that they may be moved between their first and second positions, may both be changed. In particular the longitudinal extent of the heating and cooling members may be increased so that they follow a greater part of the circumference of the two rollers without the need for separate hinged cover plates such as 121. This extension may be effected whatever the form of the heating surface of the heating units and whether these surfaces intersect the external common tangents to the rollers or not. The longitudinal extent of the heating and cooling members may be restricted and these may even terminate below the lower arc of the upper roller and above the lower arc of the upper roller. Inevitably the rate of heat transfer to the yarn is thereby reduced, but there is still the advantage that a wrap detector located in the space between the rollers and the heating units can be used. The form of the wrap detector may be changed, the available space being adequate to house other conventional forms of wrap detector, such as those based on photoelectric or microswitch techniques. However, it is preferred to use the form of wrap detector described and claimed in our copending application No. 28869/71. Although the Figures show the rollers as being cylindrical these may alternatively be of tapered form.

In the form of heater where the heating members are hinged to the housing for pivotal movement between their first and second positions, means other than the magnets described may be used for holding the heating members in their first positions. For example, the carrier of each heating member may have a bolt slidably mounted thereon, the bolt being movable to engage the housing to prevent movement of the heating member from its first position until the bolt is released. The mounting in this arrangement may be such that the heating members may pivot through almost a right angle in moving to their second positions, so fully exposing the space between the rollers. Other formsof locking or holding arrangement are also possible.

What I claim is:

1. A yarn heatercomprising:

a. two rollers mounted on spaced substantially parallel shafts;

b. bearings located in a housing and supporting said shafts;

c. two heating members extending longitudinally on opposite sides of the space between said rollers and having heating surfaces facing into the space between the rollers; and

d. a slideway for each heating member, each slideway being located on the housing and extending transversely to the shafts of therollers so that the respective heating member may slide between a first position immediately adjacent to the space between the rollers and a second position removed from said space.

2. A yarn heater according to claim 1 in which one or each heating member comprises a carrier and a heating plate having said heating surface, the heating plate being removably mounted on the carrier and the car- 6. A yarn heater according to claim in which the heating surface of one or each heating member is planar.

7. A yarn heater according to claim 1 and including a wrap detector mounted in the space between the rollers and the heating surface.

8. A yarn heater according to claim 7 in which the wrap detector has parts adjacent to both rollers.

9. A yarn heater according to claim 1 and including a further heating element mounted in the space between the, rollers and the heating members.

10. A yarn heater according to claim 9 in which the further heating element has heating surfaces at each side thereof, each of said surfaces facing towards the heating surface of one of the heating members.

11.'A yarn heater comprising:

a. two rollers mounted on spaced substantially parallel shafts;

b. bearings located in a housing and supporting said shafts;

c. two heating members extending longitudinally on opposite sides of the space between the said rollers, each heating member comprising a carrier and a heating plate having a heating surface, the heating plate being removably mounted on the carrier; and

tions. 

1. A yarn heater comprising: a. two rollers mounted on spaced substantially parallel shafts; b. bearings located in a housing and supporting said shafts; c. two heating members extending longitudinally on opposite sides of the space between said rollers and having heating surfaces facing into the space between the rollers; and d. a slideway for each heating member, each slideway being located on the housing and extending transversely to the shafts of the rollers so that the respective heating member may slide between a first position immediately adjacent to the space between the rollers and a second position removed from said space.
 2. A yarn heater according to claim 1 in which one or each heating member comprises a carrier and a heating plate having said heating surface, the heating plate being removably mounted on the carrier and the carrier being mounted on the slideway.
 3. A yarn heater according to claim 2 in which both carriers are mounted on slideways and are linked so that the two carriers move simultaneously in opposite directions.
 4. A yarn heater according to claim 1 in which the heating surface of one or each heating member is convex towards the space between the rollers.
 5. A yarn heater according to claim 4 in which one or each convex heating surface twice intersects the external common tangent plane to the rollers at the respective side of the space.
 6. A yarn heater according to claim 1 in which the heating surface of one or each heating member is planar.
 7. A yarn heater according to claim 1 and including a wrap detector mounted in the space between the rollers and the heating surface.
 8. A yarn heater according to claim 7 in which the wrap detector has parts adjacent to both rollers.
 9. A yarn heater according to claim 1 and including a further heating element mounted in the space between the rollers and the heating members.
 10. A yarn heater according to claim 9 in which the further heating element has heating surfaces at each side thereof, each of sAid surfaces facing towards the heating surface of one of the heating members.
 11. A yarn heater comprising: a. two rollers mounted on spaced substantially parallel shafts; b. bearings located in a housing and supporting said shafts; c. two heating members extending longitudinally on opposite sides of the space between the said rollers, each heating member comprising a carrier and a heating plate having a heating surface, the heating plate being removably mounted on the carrier; and d. a slideway for each heating member, said slideway being located on the housing and extending transversely to the shafts of the rollers so that each respective heating member may slide between a first position immediately adjacent to the space between the rollers and a second position removed from said space, the carriers of the heating members being linked together so that the two heating members move simultaneously in opposite directions. 